The practice and teaching of medicine has evolved from one in which the student was taught anatomy as a fundamental aspect of education, and the education included dissections of human cadavers, to one in which anatomy is a small part of the overall study of medicine both in terms of class time and in experience, as dissections are less and less common. Further, many hospital workers need some knowledge of anatomy in addition to that possessed by physicians.
Traditionally, images of the interior of a patient were obtained using X-ray technology which produced two-dimensional (2D) projections, or radiographs, on a film medium, representing the total attenuation of the X-ray beam passing through the body. More recently, computerized tomography (CT) using a spiral scan or a rotating C-arm X-ray device, for example, collects X-ray data suitable for processing to determine the volumetric attenuation of the X-ray beam. This analysis produces data in a three dimensional data set of individual voxels, which may represent the specific attenuation of a volume of material centered on a resolution cell size of the imaged volume. Thus the voxels may be used to identify materials having the same or similar specific attenuation.
The data may be presented for visualization in, for example, “slices”, which represent a plane having a specific orientation with respect to the voxel data so that the specific absorption of the voxel is represented by display intensity. The specific absorption values may be used to provide a “false color” image where ranges of absorption values, or other image property, are associated with a color. Volumetric visualization may include the segmentation of the voxel data set so as to amalgamate voxels having a contiguous nature and having properties that are consistent with a specific tissue type, such as bone, fluid, or the like, so as to be representative of an organ, such as the heart, blood vessels, or a kidney. The segmented data may be used to eliminate certain organs or structures form the displayed data so as to permit better visualization of the remainder of the image, or the segmented organ or structure.
Such data may be generated from image data obtained with a three-dimensional imaging technique. Computerized tomography (CT), magnetic resonance imaging (MR) rotational C-arm radiography, and 3D ultrasound are examples. A technique of a group of related techniques such as these is often termed “an imaging modality.”
Historically, atlases of anatomical information have been produced, originally using drawings and progressing to photographs; more recently data bases of images taken with various imaging modalities have been produced and the images may be displayed with manually applied anatomical identification. Generally these are sparse representations of the overall data set, as the overall quantity of data is considered too great for human comprehension.